docs: def guess_payload_class(self, payload):
          """DEV: Guesses the next payload class from layer bonds. Can be overloaded to use a different mechanism."""
          for t in self.aliastypes:
              for fval, cls in t.payload_guess:
                  ok = 1
                  for k in fval.keys():
                      if not hasattr(self, k) or fval[k] != self.getfieldval(k):
                          ok = 0
                          break
                  if ok:
                      return cls
          return self.default_payload_class(payload)